Vehicle for Filing a Hydrogen Storage Vessel at Enhanced Flow Rates

ABSTRACT

A compressed gas delivery vehicle includes a cooling system designed to cool the interior of a gas storage vessel containing adsorbent or absorbent material during filling of the vessel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/870,655, filed Dec. 19, 2006.

BACKGROUND

Current methods and equipment for delivering hydrogen gas to customersinclude pipelines, compressed gas trucks (tube trailers), liquidhydrogen tanks, as well as compressed gas cylinders, alone or packed incylinder bundles. In the case of pipelines, hydrogen is transferred fromproduction plants to industrial plants that consume large amounts ofhydrogen. These types of pipelines are limited to large industrialbasins is where this delivery method is economical. In the case of tubetrailers, compressed gas can be discharged into a compressed gasstationary storage system, such as a compressed gas tank or a bank ofcylinder bundles. In the case of delivery using cylinders, cylinders orcylinder bundles are simply unloaded from a vehicle onto the customerstorage area. In the case of liquid hydrogen, the liquid is usuallytransferred to a stationary liquid tank at the customer facility.

A typical compressed hydrogen installation at a customer facility can bemade of two cylinder bundles with 100 to 250 Nm³ of hydrogen dependingon local industrial practice. One cylinder bundle will typically occupya surface of 1 meter×1 meter, and the installation comprising the twobundles and space necessary to load them to, and unload them from, atruck will have a typical footprint of 1 meter×4 meters, excludingsecurity fencing and surface free from any structure according toapplicable regulations.

Storage of hydrogen in metal hydride (or other hydrogen-absorbingmaterials) tanks offers a much higher volumetric density than compressedgas. This type of storage has been demonstrated in several research anddevelopment efforts, one application of which includes supplyinghydrogen to fuel cells in military submarines. However, it is notpractical to store hydrogen in metal hydride tanks onboard trucks fordelivery because of the low gravimetric storage density of knownhydrogen-absorbing materials. One of the requirements of these types ofstorage tanks is that they include a cooling/heating subsystem forcooling the hydrogen-absorbing material upon filling and heating it upondischarge, because the heat of hydrogen absorption must be removedduring filling and the heat of desorption must be provided duringdischarge.

As an example of the storage capacity afforded by metal hydrides, FeTiH₂can contain approximately 1000 NM³ of hydrogen per cubic meter ofmaterial. Even with the cooling path and heat exchange materialinserted, the volumetric density of stored hydrogen can be much higher.200 liters of hydrogen-absorbing material is sufficient to store 200 Nm³of hydrogen. The heat of absorption of hydrogen in FeTi is approximately30 kJ/mol H₂ or 0.37 kWh/Nm³H₂.

In a scenario where hydrogen in a stationary storage device using ahydrogen-absorbing material is consumed slowly between refills but wherefilling must be done quickly for economical reasons, cooling ratebecomes the limiting factor. There are several examples of metal hydridestorage technologies with means of heat transfer, including those foundin: U.S. Pat. No. 3,943,719 (hydride-dehydride power system); U.S. Pat.No. 4,016,836 (hydride tank on-board a motor vehicle with heat transferbetween the vehicle's radiator and the hydride tank); U.S. Pat. No.6,182,717 (process for filling a metal hydride tank on-board a vehiclewith heat transfer between the vehicie's tank and the filling station'sstationary metal hydride tank; U.S. Pat. No. 6,918,430 (on-board metalhydride storage in vehicles with heat transfer system); U.S. Pat. No.6,860,923 (on-board metal hydride storage in vehicles with heat transfersystem); US 2005-0139493 (on-board metal hydride storage in vehicleswith heat transfer system); and US 2004-0042957 (thermal hydrogencompressor using metal hydrides).

SUMMARY

There is disclosed a first embodiment of a vehicle for filling a gasstorage tank that includes: a chassis; a hydrocarbon fuel tank; aninternal combustion engine borne by the chassis and being adapted andconfigured to combust hydrocarbon fuel from the hydrocarbon fuel tank toproduce power for propelling the vehicle; a radiator including a pump, acoolant conduit, and a fan, the radiator pump adapted and configured topump coolant through or from the radiator coolant conduit, the radiatorfan being adapted and configured to blow air at the radiator coolantconduit to remove heat from radiator fluid flowing therethrough; acompressed gas tank borne by the chassis and having an outlet valve; anda cooling system borne by the chassis, the cooling system comprising apump, a cooling conduit, and a fan, the cooling system pump beingadapted and configured to pump coolant through or from the coolingsystem cooling conduit, the cooling system fan being adapted andconfigured to blow air at the cooling system cooling conduit to removeheat from coolant flowing therethrough.

The first embodiment may include one or more of the following aspects:

-   -   a coolant outlet conduit having first and second ends, the first        coolant outlet conduit end extending from the cooling system,        the second coolant outlet conduit end being adapted and        configured to be coupled with a coolant fluid inlet of a gas        storage vessel with a liquid-tight seal; and a coolant inlet        conduit having first and second ends, the first coolant inlet        conduit end extending from the cooling system, the second        coolant outlet conduit end being adapted and configured to be        coupled with a coolant fluid outlet of a gas storage vessel with        a liquid-tight seal.    -   a compressed gas dispenser having first and second ends, the        first dispenser end extending from the outlet valve and being in        selective fluid communication with an interior of the compressed        gas tank via the outlet valve, the second dispenser end being        adapted and configured to be coupled with a compressed gas inlet        of a gas storage vessel with a gas-tight seal.    -   the cooling system has a cooling power of 2-500 kW.    -   the cooling system has a cooling power of 50-150 kW.

There is disclosed a second embodiment of a vehicle for filling a gasstorage tank that includes: a chassis; a hydrocarbon fuel tank; aninternal combustion engine borne by the chassis and being adapted andconfigured to combust hydrocarbon fuel from the hydrocarbon fuel tank toproduce power for propelling the vehicle; a compressed gas tank borne bythe chassis and having an outlet valve; a cooling system borne by thechassis, said cooling system comprising a pump, a cooling conduit havingfirst and second ends, and a fan, said pump being adapted and configuredto pump coolant through or from the cooling conduit, said fan beingadapted and configured to blow air at the cooling conduit; first andsecond valves; a first radiator hose extending from and in fluidcommunication with an interior of the engine and extending to and inselective fluid communication with the first valve; a second radiatorhose extending from and in fluid communication with an interior of theengine and extending to and in selective fluid communication with thesecond valve; a coolant outlet conduit extending from and in selectivefluid communication with the first valve and terminating at an end thatis adapted and configured to be coupled with a coolant fluid inlet of agas storage vessel with a liquid-tight seal; a coolant inlet conduitextending from and in selective fluid communication with the secondvalve and terminating at an end that is adapted and configured to becoupled with a coolant fluid outlet of a gas storage vessel with aliquid-tight seal.

The second embodiment may include one or more of the following aspects:

-   -   a compressed gas dispenser having first and second ends, the        first dispenser end extending from the outlet valve and being in        selective fluid communication with an interior of said        compressed gas tank via said outlet valve, said second dispenser        end being adapted and configured to be coupled with a compressed        gas inlet of a gas storage vessel with a gas-tight seal.    -   the cooling system has a cooling power of 2-500 kW.    -   the cooling system has a cooling power of 50-150 kW.

One of ordinary skill in the art will understand that the chassis is notintended to be limited to only unitary structures. As an example, thechassis may also be a multi-part chassis such as those used byreticulated trailers.

BRIEF DESCRIPTION OF THE DRAWINGS

For a further understanding of the nature and objects of the presentinvention, reference should be made to the following detaileddescription, taken in conjunction with the accompanying drawings, inwhich like elements are given the same or analogous reference numbersand wherein:

FIG. 1 is a schematic of one embodiment of the disclosed vehicle duringa filling operation including heat transfer between the storage tank andan auxiliary radiator.

FIG. 2 is a schematic of another embodiment of the vehicle during afilling operation including heat transfer between the storage tank and aradiator of the vehicle.

FIG. 3 is a schematic of a portion of the embodiment of FIG. 2.

DESCRIPTION OF PREFERRED EMBODIMENTS

For convenience, Table I recites descriptions of all the referencecharacters in the Figures.

TABLE I Reference Characters Used in Figures  1 vehicle  3 compressedgas container  4 compressed gas container outlet conduit  5a coolingsystem outlet valve  5b cooling system outlet conduit  5c chilledcoolant fitting  5e gas storage vessel coolant inlet valve  6 chilledcoolant outlet conduit  7a cooling system inlet valve  7b cooling systeminlet conduit  7c warm coolant fitting  7e gas storage vessel coolantoutlet valve  8 warm coolant inlet conduit  9a compressed gas outletvalve  9b compressed gas outlet conduit  9c compressed gas fitting  9ehydrogen storage vessel inlet valve 11 gas storage vessel heat exchangeconduit 13 gas storage vessel 15 cooling system heat exchange conduit 17cooling system 19 internal combustion engine 20 hydrocarbon fuel tank 21radiator 25 second radiator valve 27 radiator heat exchange conduit 31first radiator valve 32 second radiator hose 33 first radiator hose

In the field of gas storage, adsorption is a process that occurs when agas accumulates on the surface or in pores of a solid, forming amolecular or atomic film (the adsorbate). On the other hand, absorptionis a physical or chemical phenomenon or a process in which atoms,molecules, or ions enter some bulk phase of gas, liquid or solidmaterial. Absorption is a different process from adsorption, since themolecules are taken up by the volume, not by surface. Either of thesetwo processes will release heat of enthalpy because the atoms,molecules, or ions reach a lower energy state when absorbed or adsorbed.Conversely, energy must be supplied to the sorptive material in order todesorb the atoms, molecules, or ions.

When gas is supplied to a sorptive material within a storage vessel, theheat of enthalpy released increases the temperature of the material. Asthe temperature of the material increases, continued sorption of the gasby the material becomes more difficult. For practical purposes, it isdesirable to fill such a vessel relatively quickly. So, the pressure ofthe gas being supplied to the vessel must be increased over time inorder to maintain a desired rate at which the vessel is filled with thegas, as the temperature inside the vessel increases over time. Thus,heat transfer to the outside of the vessel often serves as the limitingfactor in achieving a desirable filling time and filling rate.

One solution is to remove heat from the vessel being filled. This istypically achieved by flowing coolant fluid through a heat exchangeconduit within the sorptive material and some sort of cooling devicepermanently associated with the vessel. However, this necessitates thata cooling device be provided with each storage vessel thereby increasingthe capital cost. Additionally, the footprint of the vessel would alsobe increased, thereby requiring additional costs for civil engineering,concrete pad construction and fencing, depending on local requirements.

In order to avoid both of these problems, there is disclosed a vehiclefor transporting compressed gas and filling a gas storage vessel withthe compressed gas, wherein the vehicle includes a cooling system. Oneimportant advantage of such a solution is that a single cooling systemon the vehicle can be used for frequent filling operations at severalcustomer locations on a delivery route. Thus, there would be no need toinvest in one cooling system for each and every storage vessel. If thevessel is infrequently refilled, such as in a fuel cell system forelectrical power backup, removing the need to invest in a cooling systemonly for use when refilling the storage vessel is especially economical.

Generally, the storage vessel may use any combination of adsorbentmaterial and gas that exhibits reversible adsorption. One of ordinaryskill in the art will recognize that the patent literature is repletewith descriptions of adsorbents that reversibly adsorb gases and theirdetails need not be replicated here in full. However, non-limitingexamples of adsorbent material include activated carbon, zeolitematerials, activated alumina, aluminosilicates, silica gel, and porousglass. Non-limiting examples of gases used with an adsorbent includehydride and halide gases, such as silane, diborane, propane, methane,natural gas, germane, ammonia, stibine, hydrogen sulfide, hydrogenselenide, hydrogen telluride, and corresponding and other halide(chlorine, bromine, iodine, and fluorine) gaseous compounds such as NF₃,and organometallic Group V compounds such as (CH₃)₃Sb.

Also generally speaking, the current method and system may be performedwith any combination of absorbent material and gas that exhibitsreversible absorption. One of ordinary skill in the art will recognizethat the patent and non-patent literature is replete with descriptionsof absorbents that reversibly absorb gases and their details need not bereplicated here. However, one particularly preferred combination of gasand absorbent material is that of hydrogen and a metal hydride.Non-limiting examples of metal hydrides include Mg₂NiH₄, NaAlH₄,LaNi₅H₆, MgH₂, FeTiH₂, Na₃AlH₆, CaNi₅H₆, and LaNi₄H₆, and other advancedmetal hydrides believed to reversibly absorb hydrogen such as Li₃AlH₆,LiMg(AlH₄)₃, LiNH₂—MgH₂, and K₂LiAlH₆.

In the case of hydrogen, the storage vessel may itself be part of a morecomplex energy system at a customer location where it is connected to astationary hydrogen consumption device not borne by the vehicle. Oneexample is a regenerative energy system comprising photovoltaic(s)panel(s) and/or wind mill(s) for supplying electricity, an electrolyzer,and a fuel cell. Hydrogen produced by the electrolyzer is stored in thestorage vessel. When the electrical power output of the photovoltaic(s)panel(s) and/or the wind mill(s) is insufficient for the demand, thefuel cell consumes hydrogen and air (or oxygen) to produce asupplemental or alternative supply of electricity.

As best illustrated in FIG. 1, in one embodiment a vehicle (1) has anonboard compressed gas container (3) and an onboard cooling system 17.During a filling operation, gas from compressed gas container 3 flowsthrough compressed gas container outlet conduit 4, compressed gas outletvalve 9 a and into compressed gas outlet conduit 9 b. One of ordinaryskill in the art will recognize that fitting 9 c (as well as fittings 5c, 7 c) comprises the combination of devices permanently attached to theend of conduit 5 b and inlet valve 5 e that are adapted to provide agas-tight seal between conduit 5 b and valve 5 e. As the gas is sorbedon sorbent material contained in gas storage vessel 13, heat isgenerated.

In order to achieve a relatively fast fill rate, a cooling system 17 isemployed with the gas storage vessel 13. A coolant fluid is chilled atcooling system 17 while traversing cooling system heat exchange conduit15. Chilled coolant is pumped out of the cooling system 17 via coolingsystem outlet valve 5 a and into cooling system outlet conduit 5 b. Achilled coolant fitting 5 c connects cooling system outlet conduit 5 band gas storage vessel coolant inlet valve 5 d. The chilled coolantflows past gas storage vessel coolant inlet valve 5 e and into gasstorage vessel heat exchange conduit 11.

As best shown in FIG. 1, heat generated by filling gas storage vessel 13with the gas is removed by coolant fluid traversing conduit 11. Thewarmed coolant fluid returns to cooling system 17 via gas storage vesselcoolant outlet valve 7 d, warm coolant fluid fitting 7 c, cooling systeminlet conduit 7 b, and cooling system inlet valve 7 a. The coolingsystem also includes a pump, which one of ordinary skill in the art willrecognize that a pump may be located anywhere along the coolant fluidpath, and an expansion tank serving as a reservoir for coolant fluid andbuffer for moderating pressure fluctuations in the coolant fluid path.

In the FIG. 1 embodiment, coolant fluid from the internal combustionengine 19 is separately cooled by radiator 21.

In an alternative embodiment and as best illustrated in FIGS. 2 and 3,the vehicle 1 need not have an onboard cooling system 17. Rather, thecoolant fluid may be chilled with vehicle radiator 21, In this case,chilled coolant fluid is pumped from radiator 21 through chilled coolantoutlet conduit 6 and warmed coolant fluid returns to radiator 21 viawarm coolant inlet conduit 8.

As more particularly shown in FIG. 3, during a filling operation secondradiator valve 25 is actuated to prevent flow of coolant from secondradiator hose 32 to radiator 21 while allowing coolant flow from warmcoolant inlet conduit 8 to radiator 21. Also, first radiator valve 31 isactuated to prevent flow of coolant from radiator 21 to first radiatorhose 33 while allowing coolant flow from radiator 21 to chilled coolantinlet conduit 6. In this manner, warm coolant from the gas storagevessel 13 flows through warm coolant inlet conduit 8 and into radiatorheat exchange conduit 27 where it is cooled with the fan. Chilledcoolant then flows to the vessel 13 via coolant inlet conduit 6.

Conversely, in between fills the engine may be cooled by actuatingsecond radiator valve 25 to allow flow of coolant from second radiatorhose 32 to radiator 21 and prevent flow of coolant from warm coolantinlet conduit 8 to radiator 21. Also, first radiator valve 31 isactuated to allow flow of coolant from radiator 21 to first radiatorhose 33 while preventing coolant flow from radiator 21 to chilledcoolant inlet conduit 6. With first and second valves 25, 31 in theselatter orientations, coolant from engine 19 may be cooled at radiator21.

For obvious reasons, one of ordinary skill in the art will recognizethat, in the embodiment of FIGS. 2 and 3, the conduits, valves, andfittings on the vehicle associated with the coolant path of the gasstorage vessel need not be specifically disposed in the locationsillustrated by the Figures. Rather, they may be located anywhere on thevehicle 1 so long as they suitably perform their functions.

While not depicted, a temperature control system is advantageously usedto activate the coolant fluid pump and coolant fluid flow in order toprovide the proper cooling rate while filling the storage tank.

Both refrigeration system and radiators are suitable for use as thecooling system. The heat exchange surface area and cross-sectionaldimension of the cooling conduit of the cooling system (or radiator inthe case of the embodiment of FIGS. 2-3), the diameter of the coolingsystem outlet and inlet conduits, and the heat exchange surface area andcross-sectional dimension of the gas storage vessel heat exchangeconduit may be sized to accommodate the cooling capacity required forfilling a gas storage vessel at a certain mass flow rate. It is wellwithin the knowledge of one of ordinary skill in the art to utilizeexisting heat exchange models in engineering texts in designing thecooling system. In the case of the heat exchange conduit of the gasstorage vessel, it is also well within the knowledge of one of ordinaryskill in the art to utilize existing teachings on heat exchangers foruse with gas adsorbent or absorbent systems.

For hydrogen storage vessels containing metal hydride absorbent materialin particular, the patent literature is replete with teachings ofsuitable vessel and heat exchanger designs such that their details neednot be duplicated herein. Representative ones include published U.S.patent application US 2005/0211573, published Japanese patentapplication JP63-035401 A, and U.S. Pat. Nos. 4,609,038; 6,709,497;6,708,546; 6,666,034; 6,638,348; 6,530,233, 6,432,379; 6,267,229; and6,015,041.

For silane storage vessels containing a zeolite material as anadsorbent, one of ordinary skill in the art may advantageously utilizethe teachings of U.S. Pat. No. 6,660,063.

Alternatively, the required cooling capacity of the gas storage vesselmay be empirically determined and the cooling system selected accordingto the determined capacity. In such a case, empirical testing may bedesigned according to an estimated required cooling capacity. Theestimated required cooling capacity may be roughly calculated bymultiplying the molar heat of enthalpy of the sorption reaction betweenthe gas and the sorbent material (which is well known in the art) by themass flow rate (in moles per unit time) of the gas. Based upon thisrough estimate of the cooling capacity of the gas storage vessel, anoff-the-shelf refrigeration system or radiator with rated coolingcapacity may be selected. The suitability of such a selected coolingsystem may be easily and empirically determined by filling the gasstorage vessel while monitoring its temperature. As an example, fillinga 200 Nm³ FeTi hydride storage tank in one hour would require a coolingpower of 75 kW. As further examples, filling a 10, 800, or 1,300 Nm³FeTi hydride storage tank in one hour would require a cooling power of4, 300, or 500 kW, respectively. This is well in the ability of currentradiators used in trucks having a 150-250 kW power engine. In the caseof the embodiment of FIGS. 2-3, the vehicle radiator may be over-sizedto accommodate the required cooling capacity of both the internalcombustion engine while running and the gas storage vessel duringfilling. Preferably, the cooling system (or radiator in the embodimentof FIGS. 2-3) has a cooling power of about 2-500 kW, and more preferablyabout 50-150 kW.

It should be noted that in each of the embodiments, the vehicle 1 ispropelled by combustion of a hydrocarbon fuel in fuel tank 20 byinternal combustion internal combustion engine 19.

Preferred processes and apparatus for practicing the present inventionhave been described. It will be understood and readily apparent to theskilled artisan that many changes and modifications may be made to theabove-described embodiments without departing from the spirit and thescope of the present invention. The foregoing is illustrative only andother embodiments of the integrated processes and apparatus may beemployed without departing from the true scope of the invention definedin the following claims.

1. A vehicle for filling a gas storage tank, comprising: a chassis; ahydrocarbon fuel tank; an internal combustion engine borne by saidchassis and being adapted and configured to combust hydrocarbon fuelfrom said hydrocarbon fuel tank to produce power for propelling saidvehicle; a radiator comprising a pump, a coolant conduit, and a fan,said radiator pump adapted and configured to pump coolant through orfrom said radiator coolant conduit, said radiator fan being adapted andconfigured to blow air at said radiator coolant conduit to remove heatfrom radiator fluid flowing therethrough; a compressed gas tank borne bysaid chassis and having an outlet valve; and a cooling system borne bysaid chassis, said cooling system comprising a pump, a cooling conduit,and a fan, said cooling system pump being adapted and configured to pumpcoolant through or from said cooling system cooling conduit, saidcooling system fan being adapted and configured to blow air at saidcooling system cooling conduit to remove heat from coolant flowingtherethrough.
 2. The vehicle of claim 1, further comprising: a coolantoutlet conduit having first and second ends, said first coolant outletconduit end extending from said cooling system, said second coolantoutlet conduit end being adapted and configured to be coupled with acoolant fluid inlet of a gas storage vessel with a liquid-tight seal;and a coolant inlet conduit having first and second ends, said firstcoolant inlet conduit end extending from said cooling system, saidsecond coolant outlet conduit end being adapted and configured to becoupled with a coolant fluid outlet of a gas storage vessel with aliquid-tight seal.
 3. The vehicle of claim 1, further comprising: acompressed gas dispenser having first and second ends, said firstdispenser end extending from said outlet valve and being in selectivefluid communication with an interior of said compressed gas tank viasaid outlet valve, said second dispenser end being adapted andconfigured to be coupled with a compressed gas inlet of a gas storagevessel with a gas-tight seal.
 4. The vehicle of claim 1, the coolingsystem has a cooling power of 2-500 kW.
 5. The vehicle of claim 1, thecooling system has a cooling power of 50-150 kW.
 6. A vehicle forfilling a gas storage tank, comprising: a chassis; a hydrocarbon fueltank; an internal combustion engine borne by said chassis and beingadapted and configured to combust hydrocarbon fuel from said hydrocarbonfuel tank to produce power for propelling said vehicle; a compressed gastank borne by said chassis and having an outlet valve; a cooling systemborne by said chassis said cooling system comprising a pump, a coolingconduit having first and second ends, and a fan, said pump being adaptedand configured to pump coolant through or from said cooling conduit,said fan being adapted and configured to blow air at said coolingconduit; first and second valves; a first radiator hose extending fromand in fluid communication with an interior of said engine and extendingto and in selective fluid communication with said first valve; a secondradiator hose extending from and in fluid communication with an interiorof said engine and extending to and in selective fluid communicationwith said second valve; a coolant outlet conduit extending from and inselective fluid communication with said first valve and terminating atan end that is adapted and configured to be coupled with a coolant fluidinlet of a gas storage vessel with a liquid-tight seal; a coolant inletconduit extending from and in selective fluid communication with saidsecond valve and terminating at an end that is adapted and configured tobe coupled with a coolant fluid outlet of a gas storage vessel with aliquid-tight seal.
 7. The vehicle of claim 6, further comprising: acompressed gas dispenser having first and second ends, said firstdispenser end extending from said outlet valve and being in selectivefluid communication with an interior of said compressed gas tank viasaid outlet valve, said second dispenser end being adapted andconfigured to be coupled with a compressed gas inlet of a gas storagevessel with a gas-tight seal.
 8. The vehicle of claim 6, the coolingsystem has a cooling power of 2-500 kW.
 9. The vehicle of claim 6, thecooling system has a cooling power of 50-150 kW.